/*
 * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//httpclient/src/java/org/apache/commons/httpclient/methods/multipart/StringPart.java,v 1.11 2004/04/18 23:51:37 jsdever Exp $
 * $Revision: 480424 $
 * $Date: 2006-11-29 06:56:49 +0100 (Wed, 29 Nov 2006) $
 *
 * ====================================================================
 *
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.commons.httpclient.methods.multipart;

import java.io.OutputStream;
import java.io.IOException;

import org.apache.commons.httpclient.util.EncodingUtil;
import org.apache.commons.logging.Log;

/**
 * Simple string parameter for a multipart post
 * 
 * @author <a href="mailto:mattalbright@yahoo.com">Matthew Albright</a>
 * @author <a href="mailto:jsdever@apache.org">Jeff Dever</a>
 * @author <a href="mailto:mbowler@GargoyleSoftware.com">Mike Bowler</a>
 * @author <a href="mailto:oleg@ural.ru">Oleg Kalnichevski</a>
 * 
 * @since 2.0
 */
public class StringPart extends PartBase {

	/** Log object for this class. */
	// private static final Log LOG = LogFactory.getLog(StringPart.class);

	/** Default content encoding of string parameters. */
	public static final String DEFAULT_CONTENT_TYPE = "text/plain";

	/** Default charset of string parameters */
	public static final String DEFAULT_CHARSET = "US-ASCII";

	/** Default transfer encoding of string parameters */
	public static final String DEFAULT_TRANSFER_ENCODING = "8bit";

	/** Contents of this StringPart. */
	private byte[] content;

	/** The String value of this part. */
	private String value;

	/**
	 * Constructor.
	 * 
	 * @param name
	 *            The name of the part
	 * @param value
	 *            the string to post
	 * @param charset
	 *            the charset to be used to encode the string, if
	 *            <code>null</code> the {@link #DEFAULT_CHARSET default} is used
	 */
	public StringPart(String name, String value, String charset) {

		super(name, DEFAULT_CONTENT_TYPE, charset == null ? DEFAULT_CHARSET
				: charset, DEFAULT_TRANSFER_ENCODING);
		if (value == null) {
			throw new IllegalArgumentException("Value may not be null");
		}
		if (value.indexOf(0) != -1) {
			// See RFC 2048, 2.8. "8bit Data"
			throw new IllegalArgumentException(
					"NULs may not be present in string parts");
		}
		this.value = value;
	}

	/**
	 * Constructor.
	 * 
	 * @param name
	 *            The name of the part
	 * @param value
	 *            the string to post
	 */
	public StringPart(String name, String value) {
		this(name, value, null);
	}

	/**
	 * Gets the content in bytes. Bytes are lazily created to allow the charset
	 * to be changed after the part is created.
	 * 
	 * @return the content in bytes
	 */
	private byte[] getContent() {
		if (content == null) {
			content = EncodingUtil.getAsciiBytes(value);
		}
		return content;
	}

	/**
	 * Writes the data to the given OutputStream.
	 * 
	 * @param out
	 *            the OutputStream to write to
	 * @throws IOException
	 *             if there is a write error
	 */
	protected void sendData(OutputStream out) throws IOException {
		// LOG.trace("enter sendData(OutputStream)");
		out.write(getContent());
	}

	/**
	 * Return the length of the data.
	 * 
	 * @return The length of the data.
	 * @throws IOException
	 *             If an IO problem occurs
	 * @see org.apache.commons.httpclient.methods.multipart.Part#lengthOfData()
	 */
	protected long lengthOfData() throws IOException {
		// LOG.trace("enter lengthOfData()");
		return getContent().length;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.commons.httpclient.methods.multipart.BasePart#setCharSet(java
	 * .lang.String)
	 */
	public void setCharSet(String charSet) {
		super.setCharSet(charSet);
		this.content = null;
	}

}
